Roots are vital biosynthetic and absorbing organs in higher plants. They have been shown to be a major source of novel naturally occurring polypeptides, alkaloids, and growth hormones. Some of these compounds have antiviral and anticancer properties. However a fundamental understanding of the cellular and molecular of the regulation of root growth is lacking. We propose to use the roots of genetically uniform lines of Zea mays (corn), Phaseolus vulgaris (bean) and Arabidopsis thaliana to study root growth and development. The meristematic region of roots may be disrupted by cold stress. We will use cold stress to perturb this developmentally important region and examine changes that occur in roots anatomically and morphologically. Specifically, using immunoreagents, we will study changes in hormone concentration and distribution on a tissue and cellular level normal and cold stressed roots. We will examine levels of plant growth regulators during lateral root induction and initiation. We will determine whether cytokinins and auxins form a concentration gradient in roots which may serve as a morphogenetic gradient in these tissues. We will define how the quiescent center maintains its developmental isolation. The results from these sets of experiments will allow us to present refined hypotheses on how normal root organization is maintained, how root architecture is effected by endogenous plant growth regulators, and how roots respond to cold stress. In addition it will support and increase the participation in science of one minority undergraduate, one minority graduate student and one minority faculty.